CRAC Channel Deficiency in Immunity to Infection

描述（由申请人提供）：本资助申请中提出的研究的长期目标是了解免疫系统细胞中钙离子流入对感染免疫的作用，以及作为免疫缺陷的原因。我们的中心假设是，通过所谓的CRAC通道的钙内流是T细胞功能所必需的，因此对感染具有免疫力。我们将研究CRAC通道功能遗传缺陷的患者，并在感染动物模型中使用CRAC通道基因缺失的小鼠。 我们以前的研究表明，CRAC通道功能有遗传缺陷的患者在生命早期会遭受复发性、危及生命的感染。CRAC通道由基因的奥赖和STIM家族的成员编码。我们确定了第一个患者与突变的ORAI1和STIM1基因。他们患有一种独特的免疫缺陷综合症，其特征是严重感染、自身免疫、肌肉张力减退以及牙齿形成和汗腺功能缺陷。CRAC通道缺陷患者的免疫缺陷归因于T细胞（白色血细胞，其活化依赖于CRAC通道）的功能受损。ORR 1和STIM 1基因的突变会消除免疫细胞中的钙内流并损害其功能，包括重要免疫调节蛋白的产生。尽管从研究细胞培养系统中CRAC通道缺陷免疫细胞的功能中获得了这些见解，但我们对CRAC通道如何使T细胞和其他免疫细胞能够对抗活生物体中的感染缺乏更深入的机制理解。除了研究CRAC通道基因遗传突变的患者外，我们还因此产生了T细胞中缺乏STIM和奥赖基因表达的基因工程小鼠。利用这些小鼠，我们最近发现CRAC通道对于T细胞介导自身免疫性疾病和提供感染免疫力的能力很重要。因此，这些小鼠将是研究CRAC通道提供宿主防御病毒以及真菌和分枝杆菌病原体感染的机制的理想工具。我们的实验室处于一个独特的位置，通过研究小鼠中发现的钙依赖性免疫调节机制的缺陷是否会导致CRAC通道突变患者的免疫缺陷，将动物模型中的发现转化为患者。 这项建议的具体目标如下：（1）。我们将分析疑似CRAC通道功能障碍的免疫缺陷患者的遗传缺陷，并研究突变如何在分子水平上干扰CRAC通道功能。(2)我们将确定T细胞中的CRAC通道控制针对急性和慢性病毒感染以及细胞内细菌的免疫力的机制。(3)我们将研究CRAC通道在宿主防御真菌感染和调节提供抗真菌免疫的T细胞功能中的作用。此外，我们将确定T细胞中的CRAC通道如何控制对慢性分枝杆菌感染的免疫反应，并提供对结核病的保护。

DESCRIPTION (provided by applicant): The long-term goal of the research proposed in this grant application is to understand the role of calcium influx in cells of the immune system for immunity to infection and as a cause of immunodeficiency. Our central hypothesis is that calcium influx through so-called CRAC channels is required for the function of T cells and thus immunity to infection. We will study patients with inherited defects in CRAC channel function and use mice with genetic deletion of CRAC channel genes in animal models of infection. We previously showed that patients with inherited defects in CRAC channel function suffer from recurrent, life-threatening infections early in life. CRAC channels are encoded by members of the ORAI and STIM family of genes. We identified the first patients with mutations in ORAI1 and STIM1 genes. They suffer from a unique immunodeficiency syndrome that is characterized by severe infections, autoimmunity, muscular hypotonia and defects in tooth formation and sweat gland function. The immunodeficiency in CRAC channel-deficient patients has been attributed to the impaired function of T cells, white blood cells whose activation is dependent on CRAC channels. Mutations in ORAI1 and STIM1 genes abolish calcium influx in immune cells and impair their function including the production of important immune regulatory proteins. Despite these insights gained from studying the function of CRAC channel-deficient immune cells in cell culture systems, we are lacking a deeper mechanistic understanding of how CRAC channels enable T cells and other immune cells to fight infections in living organisms. In addition to studying patients with inherited mutations in CRAC channel genes, we therefore generated genetically engineered mice that lack expression of STIM and ORAI genes in T cells. Using these mice we recently showed that CRAC channels are important for the ability of T cells to mediate autoimmune diseases and to provide immunity to infection. These mice will therefore be ideal tools to study the mechanisms by which CRAC channels provide host defense to infection with viruses as well as fungal and mycobacterial pathogens. Our lab is in a unique position to translate findings made in animal models into patients by investigating if defects in the calcium-dependent immunoregulatory mechanisms found in mice contribute to the immunodeficiency in patients with mutations in CRAC channels. The specific aims of this proposal are as follows: (1). We will analyze the genetic defects in immunodeficient patients with suspected CRAC channel dysfunction and investigate how mutations interfere with CRAC channel function at a molecular level. (2) We will determine the mechanisms by which CRAC channels in T cells control immunity against acute and chronic viral infections as well as intracellular bacteria. (3) We will investigate the role of CRAC channels in host defense against fungal infections and in regulating the function of T cells that provide antifungal immunity. Furthermore, we will determine how CRAC channels in T cells control immune responses to chronic mycobacterial infections and provide protection against tuberculosis.